What happened to my Ctrl-+/- zoom in Xorg?
Older X.org and XFree86 used to have this neat feature where pressing Ctrl+<numpad +> and Ctrl+<numpad -> would cycle through the screen modes defined in your config file in the "Screen" section, effectively switching screen modes on the fly and letting you pan around the full virtual screen size with the mouse.
This was a really useful feature for zooming in on small details, or to blow up videos without incurring high CPU overhead.
But since about X.org 1.7 this feature seems to be missing. I've been researching and discovered why it's missing, and what to do about it.